Yup, I felt terrible about 3 days into the diet I was following. It lasted about 3-4 days. Had achiness, stomach pains like crazy!, extremely tired, and bad D. I realized from doing my research that I was having a fungal die-off, often known as Herxheimer's response. That was a key indicator to me that my problems were fungal related. And, when I felt so much better changing my diet, another clue. The diet I followed is similar to SCD, was actually an antifungal diet/program where I took natural antifungals at the same time. I was a D, not a C. I realized during the first 2 weeks that my symptoms must have had a fungal etiology because once I quit sugar/grains/yeast(on which fungi thrive and need to survive), I felt waaaaaay better after 2 weeks. I still need to watch what I eat. I am now on a modified diet reducing sugar and grains, and absolutely no yeast if I can help it. Causes too much gas, some D, and pain. I still take my natural antifungals for maintenence. That's why I say, give it longer than a few days. Good luck!